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What impact does a journal have? Can this impact be “calculated”? These questions can be answered to some extent via the Journal Citation Reports (JCR). This is a platform that evaluates journals from the literature database Web of Science Core Collection.
Specifically, the journals that are included in these indices:
- SCIE (Science Citation Index Expanded)
- SSCI (Social Sciences Citation Index)
- AHCI (Arts & Humanities Citation Index)
- ESCI (Emerging Sources Citation Index)
The JCR was first published in 1976 and has been released annually since then (online since 1998). Various metrics can be evaluated, including Journal Impact Factor (JIF) or Journal Citation Index (JCI, since 2021). The most recent JCR from 2020 contains 20,994 journals.
The impact of a journal is calculated with the JIF:
However, the JIF also has its limitations: for the JIF of 2020, the citations of the publications of 2018 and 2019 were taken into account. In order to have an additional variable besides the 2-year JIF, the 5-year JIF was added.
A second limitation is the use of citable publications. Only articles, reviews or conference papers are considered.
The journals in the JCR can be listed in different ways: by JIF or by category (further listings by publisher or country are planned). A comparison between journals makes sense only within the same category.
Each journal has its own overview page in the JCR and the display of the different metrics (JIF, citable item, etc.).
Since the JCR and the JIF came out, it has been criticised because the JIF is often used incorrectly: (1) whether it is to assess the quality of a paper in a journal, (2) that all publications in a journal are taken into account, or (3) that the JIF is a precise value. More on the misconceptions surrounding the use of the JIF was explained in a previous blog post.
Since 2021, a new metric has been added: Journal Citation Indicator (JCI, [PDF]). This is offered for all indices, but can be used especially for AHCI and ESCI. No JIF is calculated for AHCI and ESCI. JCI is a field-normalised metric for journals that can be used for all disciplines. The categories, year of publication and document type are normalised.
There is not only the JIF or the JCI as a journal metric. Other alternative metrics are listed here:
More information on the JCR can be found in the Journal Citation Reports Help.
